The field of this invention relates to a closed crankcase ventilation system.
Government regulations relating to environmental concerns have mandated that many engines have a closed crankcase ventilation system. Commonly, these closed systems re-circulate any blow-by gases escaping from the combustion chambers and passing into the crankcase back into the air intake system. These blow-by gases, which are loaded with unburned gaseous hydrocarbons, are then re-circulated back to the intake manifold to be burned upon the next pass into the engine.
However, the crankcase gases are also usually loaded with oil droplets and moisture. The moisture condenses into water and drains from a crankvent breather. The oil that enters into the crankvent breather sits therein until normal maintenance when the breather is emptied and cleaned out. It has been known that a crankvent breather located below the rocker cover breather outlet allowed the breather canister to fill with engine oil due the downward angle of the hose leading from the outlet to the breather canister. As such, frequent maintenance was needed to empty the canister in order that it function properly.
Attempts have been made to relocate the crankvent breather to an upper intake area in the front of the engine above the rocker breather outlet. Testing showed that, as expected, the crankvent breather went a longer time before the oil filled the cannister. Vehicles fitted with the relocated breather run fine in the summer and in warm weather. However, during cold weather months, an oil emulsion was found in the oil breather cannister with the drain check valve frozen shut. With the drain blocked, the water and emulsion solidified and plugged the breather system well before the scheduled maintenance. The plugged breather system creates high crankcase pressure in the engine. The high crank pressure in the engine may push oil past the turbocharger seals and into the intake air, causing exhaust smoke.
What is needed is an expeditiously constructed crankcase ventilation system that prevents excessive oil buildup within the breather canister but can also work during cold weather.
In accordance with one aspect of the invention, a closed crankcase breather system for an internal combustion engine includes a crankvent breather with an inlet, gas outlet and water drain outlet. The crankvent breather is operably interposed between a rocker cover breather outlet and a hose leading to an intake system. The crankvent breather is located in proximity to the engine for receiving heat from the engine. Preferably, the crankvent breather is located in proximity to a rear end of the engine block and below the rocker cover breather outlet.
An inlet hose is connected to the crankvent breather inlet and in communication with the rocker cover breather outlet. An oil accumulator is in line between the rocker cover breather outlet and the inlet hose. The oil accumulator is constructed for separating oil from the exhaust gasses exiting the rocker cover breather outlet and returning the oil through the rocker cover breather outlet into said rocker cover, but allowing the exhaust gasses to pass to the crankvent breather.
Preferably, the oil accumulator and the inlet hose leading to the crankvent breather are covered by a heat insulating material to prevent the moisture in the exhaust gasses from freezing before draining from the crankvent breather. Preferably this heat insulating material is a mylar insulation material.
In accordance with another aspect of the invention, an oil accumulator for a closed crankcase ventilation system has a lower inlet connectable to a rocker breather outlet, an upright cylindrical body with a substantially flat top wall and an upper outlet spaced from downwardly from the top wall. Preferably, the lower inlet and the upper outlet are circumferentially spaced at right angles from each other about the cylindrical body. Both the inlet and outlet have a respective longitudinal axis intersecting the longitudinal axis of the cylindrical body. Preferably, a mounting flange extends from the cylindrical body. The flange is substantially planar with the top wall.
In this fashion, a closed crankcase system with a breather is provided which fills with oil more slowly and thus can have less frequent maintenance checks. The system works during cold weather conditions and prevents freezing of the moisture which may otherwise block the operation of the breather. The system works under adverse situations where a cylinder kit fails and causes significant blow by of oil and blow by gasses pass into the crankcase. In this way, the air intake system and turbo charge system are more adequately protected when a cylinder kit failure occurs.